Objective: 1) The isolation and characterization of antigens from human cancers with a view to their use in diagnosis or therapy. 2) Antigens will be isolated by affinity chromatography and other techniques in sufficient quantity to permit the preparation of adequate amounts of monospecific antisera for development of specific radioimmunoassays (RIA) for individual antigens. The clinical value of these RIA will be compared with that of currently available CEA assays. The specific RIA will be applied to feces as well as plasma. The specific antibody immunoglobulins will be radiolabeled and their use as external tumor scanning agents studied. They will also be investigated as reagents for detection of tumor cells in an automated cytodiagnostic system. Structural and immunochemical studies will be performed of the tumor associated antigens determinants before and after chemical and enzymatic modification of the antigen molecules. Concurrent attempts will be made to identify oncofetal antigens from the pancreas.